1. Field of the Invention
This invention relates to gas pressure reducing regulators. More particularly, it relates to regulators for reducing pressure of a compressed gas, such as oxygen, contained in cylinders to a working pressure level.
2. Description of the Prior Art
Gas pressure reducing regulators for reducing high pressure gas to low pressure for various applications have been known and used for many years. In addition to cutting and welding applications, such regulators are used in the medical field where for regulating gases such as oxygen which are administered to patients. Two problems associated with such regulators are burn-through and explosion. Regulator burn-through occurs when the regulator body and/or component materials are ignited and burn in the presence of oxygen or other oxidizer present within the regulator body. This burn-through is characterized by the burning through the outer walls of the regulator and a subsequent melting away of the regulator. This is often accompanied by sparks and flame.
With explosion, the detonation of gases and other flammables such as lubricant present within the regulator body occurs. If the housing does not contain the explosion, it will fragment sending shrapnel-like pieces in many directions. Either burn-out or explosion represent a serious safety hazard to those within the environment of such a regulator and could be especially damaging in hospital environments where patients and medical personnel are present.
The ignition which triggers burn-through or explosion may be caused in several ways. One way is thought to be adiabatic compression of the gases within the regulator body. The second possiblilty is the entrance into the regulator body of sparks from other sources. Whatever the cause of this safety problem, it does occur with sometimes disastrous results.
Various attempts have been made to produce a regulator that is resistant to burn-through and explosion. One such regulator design is shown in U.S. Pat. No. 4,450,858. Another is shown in U.S. Pat. No. 4,489,751. However, these prior art devices have not been entirely satisfactory.